1. Field of the Invention
The present invention relates to a power controller and a power control method, and more particularly to a power controller and a power control method, which are suitable for an integrated battery power system for vehicle.
2. Description of the Related Art
A power controller is used for solenoid driving in the battery power system for vehicles. The power controller is operated with a power supply at 12V from the battery on the vehicles. The power controller comprises MOS transistors having a high drain source withstand voltage and a high gate source withstand voltage for a high voltage of 12V.
FIG. 1 is a block diagram illustrative of a conventional power controller operable with 12V. The conventional power controller 80 has a control circuit 85, an output circuit 84 and an external load 86. The control circuit 85 generates a control signal upon receiving an input signal. The control signal is supplied to the output circuit 84. The output circuit 84 switches ON and OFF in accordance with the control signal for driving the external load 86. A maximum variation width in voltage level of the control signal is 12V. For this reason, the conventional power controller 80 comprises the transistors with the high drain source withstand voltage of 12V and the high gate source withstand voltage of 12V.
The power controller may sometime be integrated with a logic circuit operable with 5V over a single wafer for the purpose of cost reduction and size and weight reductions. In this case, the manufacturing process for the logic circuit is the base process, and the power controller operable with 12V is formed by additional processes. These additional processes make it difficult to reduce the manufacturing cost.
Japanese laid-open patent publications Nos. 10-65516 and 11-327500 disclose the use of a level converter circuit for ON-OFF control of the switching transistors provided in the high voltage power side, wherein additional circuit elements are provided, for example, a highly accurate voltage detector and a controller in the high voltage power side. These additional circuit elements make it difficult to increase the density of integration. These additional circuit elements may be hard to co-operate with the control circuit in the low voltage power side.
In the above circumstances, the development of a novel power controller and a power control method free from the above problems is desirable.
Accordingly, it is an object of the present invention to provide a novel power controller free from the above problems.
It is a further object of the present invention to provide a novel power controller suitable to be integrated with another circuit operable with a different power voltage from the power controller over a single wafer for a possible manufacturing cost reduction and possible size and weight reductions.
It is a still further object of the present invention to provide a novel power controller suitable to be integrated with another circuit operable with a different power voltage from the power controller over a single wafer for allowing additional circuit elements such as highly accurate voltage detector and controller in a high voltage power side without for realizing multi-functions, however, making the circuit configuration complicated.
It is yet a further object of the present invention to provide a novel power control method free from the above problems
It is a further object of the present invention to provide a novel power control method suitable to be integrated with another circuit operable with a different power voltage from the power controller over a single wafer for a possible manufacturing cost reduction and possible size and weight reductions.
It is a still further object of the present invention to provide a novel power control method suitable to be integrated with another circuit operable with a different power voltage from the power controller over a single wafer for allowing additional circuit elements such as highly accurate voltage detector and controller in a high voltage power side without for realizing multi-functions, however, making the circuit configuration complicated.
The present invention provides a power controller operable with at least a first power voltage and a second power voltage lower than the first power voltage. The power controller comprises: a first control signal generator operable with the second power voltage for generating a first control signal; a first reference voltage generator operable with the first power voltage for generating a first reference voltage which corresponds to a difference between the first and second power voltages; a first level converter being electrically coupled with the first control signal generator for receiving the first control signal, the first level converter being electrically coupled with the first reference voltage generator for receiving the first reference voltage, the first level converter converting the first control signal into a first level-converted control signal with a voltage level range between the first power voltage and the difference between the first and second power voltages; and a first driver electrically coupled with the first level converter for receiving the first level-converted control signal, and the first driver driving an external load in accordance with the first level-converted control signal.
The above and other objects, features and advantages of the present invention will be apparent from the following descriptions.